Epigenetic regulation of sexual development

Paradigm shift in sex chromosome evolution. 19-22 September 2019, Berlin.-- 1 page

Epigenetic regulation of sexual developmen DNA methylation is an epigenetic modification that regulates gene expression without changes in the underlying nucleotide sequence. DNA methylation patterns vary across different groups of amniote vertebrates and thus it is believed that it has contributed to sex chromosome evolution and dosage compensation. However, heteromorphic sex chromosomes are less abundant in anamniote vertebrates, where, in addition to "pure" genetic (i.e., chromosomal) sex determination (GSD) systems, other systems such as polygenic sex determination (PSD) and environmental sex determination (ESD) are frequent. Furthermore, since epigenetic regulatory mechanisms integrate genetic and environmental variation, attention is increasingly being paid to the epigenetic regulation of sex, particularly in fish and reptiles with ESD, as well as in sex-changing hermaphrodite fish. Thus, there is increasing evidence for the contribution of epigenetics in gene expression regulation during different stages of sex differentiation. Using two fish species with PSD, the zebrafish (laboratory strains) and the European sea bass, data is presented on the genetic component of epigenetic variation and the influence of temperature and population density in shaping DNA methylation patterns in key genes related to sexual development. Combining these data from data gathered in other vertebrate species, the Conserved Epigenetic Regulation of Sex (CERS) model will be presented. A derivate of this model is the possibility of identifying Essential Epigenetic Markers (EEM) that can have practical applications, for example, for sex prediction and for uncovering hidden effects of environmental perturbations in otherwise apparently morphologically normal gonads. Finally, I will present the idea that epigenetic mechanisms make transitions possible, both among different sexual systems (gonochorism and different forms of hermaphroditism) and also between different mechanisms of sex determination, favoring and regulating sexual phenotypic plasticity

Supported by Spanish Ministry of Science, Innovation and Universities grant AGL2016-78710-R to F.P.